Cannulation-Related Complications on Veno-Arterial Extracorporeal Membrane Oxygenation: Prevalence and Effect on Mortality

Cannulation-related complications are a known source of morbidity in patients supported on veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Despite its prevalence, little is known regarding the outcomes of patients who suffer such complications. This is a single institution review of cannulation-related complications and its effect on mortality in patients supported on VA-ECMO from January 2010-2015 using three cannulation strategies: axillary, femoral, and central. Complications were defined as advanced if they required major interventions (fasciotomy, amputation, site conversion). Patients were divided into two groups (complication present vs. not present) and Kaplan-Meier analysis was performed to determine any differences in their survival distributions. There were 103 patients supported on VA-ECMO: 41 (40%), 36 (35%), and 26 (25%) were cannulated via axillary, femoral, and central access, respectively. Cannulation-related complications occurred in 33 (32%) patients and this did not differ significantly between either axillary (34%), femoral (36%), or central (23%) strategies (P = 0.52). The most common complications encountered were hemorrhage and limb ischemia in 19 (18%) and 11 (11%) patients. Hemorrhagic complications did not differ between groups (P = 0.37), while limb ischemia and hyperperfusion were significantly associated with femoral and axillary cannulation, at a rate of 25% (P < 0.01) and 15% (P = 0.01), respectively. There was no difference in the incidence of advanced complications between cannulation groups: axillary (12%) vs. femoral (14%) vs. central (8%; P = 0.75). In addition, no increase in mortality was noted in patients who developed a cannulation-related complication by Kaplan-Meier estimates (P = 0.37). Cannulation-related complications affect a significant proportion of patients supported on VA-ECMO but do not differ in incidence between different cannulation strategies and do not affect patient mortality. Improved efforts at preventing these complications need to be developed to avoid the additional morbidity in an already critical patient population.

First nationwide survey of US integrated 6-year cardiothoracic surgical residency program directors

OBJECTIVE

The recently implemented integrated 6-year (I-6) format represents a significant change in cardiothoracic surgical residency training. We report the results of the first nationwide survey assessing I-6 program directors' impressions of this new format.

METHODS

A 28-question web-based survey was distributed to program directors of all 24 Accreditation Council for Graduate Medical Education-accredited I-6 training programs in November 2013. The response rate was a robust 67%.

RESULTS

Compared with graduates of traditional residencies, most I-6 program directors with enrolled residents believed that their graduates will be better trained (67%), be better prepared for new technological advances (67%), and have superior comprehension of cardiothoracic disease processes (83%). Just as with traditional program graduates, most respondents believed their I-6 graduates would be able to independently perform routine adult cardiac and general thoracic operations (75%) and were equivocal on whether additional specialty training (eg, minimally invasive, heart failure, aortic) was necessary. Most respondents did not believe that less general surgical training disadvantaged I-6 residents in terms of their career (83%); 67% of respondents would have chosen the I-6 format for themselves if given the choice. The greater challenges in training less mature and experienced trainees and vulnerability to attrition were noted as disadvantages of the I-6 format. Most respondents believed that I-6 programs represent a natural evolution toward improved residency training rather than a response to declining interest among medical school graduates.

CONCLUSIONS

High satisfaction rates with the I-6 format were prevalent among I-6 program directors. However, concerns with respect to training relatively less experienced, mature trainees were evident.

Right ventricular outflow tract obstruction after sinus of valsalva aneurysm repair

Sinus of Valsalva aneurysm (SVA) is a rare cardiac lesion especially in the western countries and older population. We report an unusual case of a 60-year-old Caucasian male with SVA, acute decompensation, and a pressurized prolapsed aortic leaflet cystic remnant via a small supracristal VSD causing recurrent right ventricular outflow tract obstruction following a Bentall procedure

"Boot camp" simulator training in open hilar dissection in early cardiothoracic surgical residency

BACKGROUND

We evaluated focused training in lung hilar dissection with a reanimated porcine lung model in the boot camp setting.

METHODS

A total of 64 first-year cardiothoracic surgical residents participated in four consecutive hours devoted to training in open hilar dissection as part of the Thoracic Surgical Directors Association boot camps. Each resident participated in two open hilar dissections. Component tasks were assessed on a 5-point rating scale for the first and second dissections.

RESULTS

Immediate assessment performed after completion of the session showed improvements in all graded components. The mean total score on a 50-point scale improved significantly between the first and second repetition (36.03 ± 7.03 to 41.16 ± 6.95; p = 0.001).

CONCLUSIONS

Focused massed (single-session) practice in the boot camp setting improved the ability of residents to perform hilar dissection on simulators using reanimated porcine lung models. Given these early successes in massed simulation-based surgical education, there is good reason to expect that deliberate and distributed practice on similar simulators would improve resident education in cardiothoracic surgery.

Elevated pre-operative serum peptides for collagen I and III synthesis result in post-surgical atrial fibrillation

OBJECTIVES

This study sought to determine if serum markers for collagen I and III synthesis, the carboxyl terminal peptide from pro-collagen I (PICP) and the amino terminal peptide from pro-collagen III (PIIINP), correlate with left atrial (LA) fibrosis and post-operative atrial fibrillation (AF).

BACKGROUND

AF after cardiac surgery is associated with adverse outcomes. We recently demonstrated that LA fibrosis is associated with post-operative AF in patients with no previous history of AF.

METHODS

Fifty-four patients having cardiac surgery without a history of AF consented to left and right atrial biopsies and a pre-operative peripheral blood draw. Picrosirius red staining quantified the percentage of fibrosis, and reverse transcriptase polymerase chain reaction assessed atrial tissue messenger ribonucleic acid transcripts involved in the fibrosis pathway. PICP and PIIINP levels were measured using an enzyme immunosorbent assay.

RESULTS

Eighteen patients developed AF, whereas 36 remained in normal sinus rhythm. LA fibrosis was higher in patients who developed AF versus normal sinus rhythm (6.13 ± 2.9% vs. 2.03 ± 1.9%, p = 0.03). LA messenger ribonucleic acid transcripts for collagen I, III, transforming growth factor, and angiotensin were 1.5- to 2.0-fold higher in AF patients. Serum PICP and PIIINP levels were highest in AF versus normal sinus rhythm (PICP: 451.7 ± 200 ng/ml vs. 293.3 ± 114 ng/ml, p = 0.006; PIIINP: 379 ± 286 pg/ml vs. 191.6 ± 162 pg/ml, p = 0.01). Furthermore, there was a linear correlation between LA fibrosis and serum PICP levels (R(2) = 0.2; p = 0.01), and of the markers, only PICP was independently associated with AF.

CONCLUSIONS

This demonstrates that serum PICP and PIIINP levels correlate with the presence of LA fibrosis and may act as predictors for post-operative AF even in the absence of previous history of AF.

Leukocyte-reduced transfusions in cardiac surgery results of an implementation trial

An implementation trial of leukocyte-reduced transfusions in cardiac surgery (primary coronary artery bypass graft and valve replacement) was performed from July to December 1998; comparisons were made with data from the same period in 1997. Patients from both periods were similar in important preoperative and intraoperative variables (age, sex, weight, number of units of RBCs transfused, ejection fraction). The mean total number of complications was statistically significantly decreasedfrom 0.26 complications per patient in the non-leukocyte-reduced to 0.19 in the leukocyte-reduced recipients. Overall, the mean +/- ISD costs of care per patient decreasedfrom 1997 ($27,615 +/- $33,973) to 1998 ($27,038 +/- $24,107). Mean costs decreased $1,700 per patient for recipients of leukocyte-reduced blood in 1998 compared with recipients of non-leukocyte-reduced blood in 1997 Mean costs increased $4,000 per patient in patients who did not receive transfusions in 1998 compared with 1997. Hospitalization costs decreased when leukocyte-reduced transfusions were implemented for patients undergoing cardiac surgery in our institution. Implementation of leukocyte reduction may be cost neutral or cost saving in at least some settings.

Update on indications for surgery in aortic insufficiency

Aortic insufficiency is a valvular disease characterized by left ventricular volume overload. This article presents a logical approach for following up patients with aortic insufficiency and helps to determine the optimal timing for valve replacement. The various valve replacement techniques are discussed, and the specific benefits or risks associated with these procedures are described.

Hemodynamic effects of chest closure in adult patients undergoing cardiac surgery

OBJECTIVE

To evaluate hemodynamic effects of sternal retractor removal and sternal closure after cardiopulmonary bypass and to correlate these changes with preoperative and intraoperative variables.

DESIGN

Prospective.

SETTING

University hospital.

PARTICIPANTS

Fifty adults undergoing cardiac surgery.

MEASUREMENTS AND MAIN RESULTS

Arterial, pulmonary artery, and transesophageal echocardiography measurements were obtained immediately before and 1 minute after removal of the sternal retractor and immediately before and 1 minute after sternal closure. Retractor removal caused a significant decrease in cardiac index by 5.6% (p < 0.01), stroke volume index by 4.0% (p < 0.05), and mean pulmonary artery pressure by 4.8% (p < 0.001). Sternal closure caused a significant decrease in cardiac index by 7.7%, stroke volume index by 10.2%, and left ventricular end-diastolic area by 9.2% (p < 0.001) There were significant increases in pulmonary capillary wedge pressure and systemic vascular resistance by 9.1% and 10.8% (p < 0.01). There was no significant change in the ejection fraction area. The magnitude of decrease in stroke volume index with sternal closure correlated positively with end-diastolic area immediately before the closure.

CONCLUSION

Chest closure is associated with significant hemodynamic changes and a change in the ventricular transmural pressure-volume relationship. Patients with lower preload immediately before closure are more vulnerable to a decrease in cardiac index. Based on the results of this study, volume appears to be the appropriate preventive and treatment option to limit the impact of chest closure.

Association of ABO-mismatched platelet transfusions with morbidity and mortality in cardiac surgery

BACKGROUND

The transfusion of ABO-mismatched platelets has been associated with increased morbidity and mortality during induction therapy for acute leukemia and allogeneic progenitor cell transplantation.

STUDY DESIGN AND METHODS

Reported here is a cohort study of 153 patients undergoing primary coronary artery bypass graft or coronary valve replacement surgery by two surgeons in one institution during 1997 and 1998. All statistics employed nonparametric two-sided tests (Mann-Whitney; Fisher's exact test).

RESULTS

Patients receiving at least one ABO-mismatched pool of platelets had a significantly longer hospital stay, more days of fever, greater total hospital charges, and more RBC transfusions. Mortality, hours in the intensive care unit, days on antibiotics, and numbers of platelet transfusions were also greater in recipients of ABO-mismatched platelets, but these differences were of less statistical significance. When the analysis was restricted to the 139 patients who received no more than two pools of platelets, the trends for increased morbidity and mortality (8.6% vs. 1.9%; p = 0.10) in recipients of ABO-mismatched platelets persisted. The number of RBC transfusions required in this latter cohort was 50 percent greater (mean, 6.1 vs. 9.2; p = 0.02), despite the fact that the number of platelet transfusions given was similar (mean, 1.2 vs. 1.3 pools; p = 0.22).

CONCLUSIONS

ABO-mismatched platelet transfusions are associated with unfavorable outcomes in cardiac surgery, a relationship that remains unexplained. As this association has been found in three cohort studies in various clinical settings, further investigation of this association is warranted.

Photo-irradiation improved functional preservation of the isolated rat heart

BACKGROUND AND OBJECTIVE

Photo-irradiation causes a variety of effects in different cells and tissues. We hypothesized that photo-irradiation may improve cardiac preservation based on these observations.

STUDY DESIGN/MATERIALS AND METHODS

For pre-storage treatment (Pre), the heart in an anesthetized open-chest rat was irradiated using an Argon-dye laser with a wavelength of 660 nm at a fluence of 16.8 J/cm2 or sham-operated. The heart was excised, perfused with Krebs-Henseleit Buffer, cardioplegically arrested, and stored by immersion at 0 degree C for 18 hrs. Functional recovery was evaluated by working reperfusion for 30 min. For post-storage treatment (Post), the isolated hearts were stored for 18 hrs at 0 degree C; laser irradiation at a fluence of 36 J/cm2 was administered during working reperfusion. Hearts which did not receive irradiation during reperfusion served as control. Furthermore, isolated cardiomyocytes were used to study laser effect on cellular ATP content, catalase activity, and nitric oxide (NO) release.

RESULTS

Both Pre and Post groups showed significant improvement in recovery of aortic flow, cardiac output, and work compared to the corresponding control groups (P < 0.05). Combined Pre/Post laser treatment did not improve function. Investigation using isolated rat cardiomyocytes found that both end-storage ATP and end-reperfusion catalase activity in the laser-treated group were significantly higher than those in the untreated cells (P < 0.05). NO release increased by 15% in the laser group after 18 hrs of 37 degrees C incubation.

CONCLUSION

Photo-irradiation improves functional recovery of the cold-stored rat heart possibly via conservation of ATP and antioxidant enzyme activity.

Lack of lung hemorrhage in humans after intraoperative transesophageal echocardiography with ultrasound exposure conditions similar to those causing lung hemorrhage in laboratory animals

This study investigated the phenomenon of ultrasonically induced lung hemorrhage in humans. Multiple experimental laboratories have shown that diagnostic ultrasound exposure can cause hemorrhage in the lungs of laboratory animals. The left lung of 50 patients (6 women, 44 men, mean age 61 years) was observed directly by the surgeon after routine intraoperative transesophageal echocardiography was performed. From manufacturer specifications the maximum derated intensity in the sound field of the system used was 186 W/cm2, the maximum derated rarefactional acoustic pressure was 2.4 MPa, and the maximum mechanical index was 1.3. The lowest frequency used was 3.5 MHz. This exposure exceeds the threshold found for surface lung hemorrhage seen on gross observation of laboratory animals. No hemorrhage was noted on any lung surface by the surgeon on gross observation. We conclude that clinical transesophageal echocardiography, even at field levels a little greater than the reported thresholds for lung hemorrhage in laboratory animals, did not cause surface lung hemorrhage apparent on gross observation. These negative results support the conclusion that the human lung is not markedly more sensitive to ultrasound exposure than that of other mammals.

Obliteration of empyema tract with deepithelialized unipedicle transverse rectus abdominis myocutaneous flap

Four patients with chronic empyema after pneumonectomy have undergone successful obliteration of the empyema tract with a deepithelialized transverse rectus abdominis myocutaneous flap. The deepithelialized skin island has provided sufficient bulk for tract obliteration. Rotation of the skin island into the long axis of the rectus muscle has added considerable length to this flap, allowing it to reach the apex of the thoracic cavity. A recurrent loculation developed 4 months after the obliteration procedure in one patient. This was successfully treated with open pleural drainage and a second Clagett procedure. Over a mean follow-up period of 35 months, all four patients are free of further infectious sequelae. Chest roentgenograms have confirmed eradication of the tracts in all four patients.

Enalaprilat, an angiotensin-converting enzyme inhibitor, enhances functional preservation during long-term cardiac preservation. Possible involvement of bradykinin and PKC

We investigated the effect of enalaprilat (ET) on long-term preservation of cardiac explant. Isolated rat hearts (n = 7/group) were pretreated with 0 to 40 nM ET and stored at 0 degree C for 16 h. Functional viability was assessed after 30-min working reperfusion without ET. Prestorage control function (mean +/- S.E.M.) (n = 7) included heart rate (HR), 291 +/- 12 bpm; aortic flow (AF). 49.8 +/- 1.9 ml/min; coronary flow (CF), 25.2 +/- 1.3 ml/min; cardiac output (CO), 75.0 +/- 1.2 ml/min; and work, 89.4 +/- 4.7 g-m/min. Post-storage function of untreated hearts was: AF, 61%; CF, 43%; CO, 55%; work, 48% of control. ET (20 nM) enhanced AF recovery to 85%; CF, 58%; CO, 76%; work, 73% of control (P < 0.05 v untreated). Hoe 140 (D-Arg-[Hyp2, Thi5,8, D-Phe7]BK) (1 nM) a bradykinin receptor antagonist, inhibited ET effect; function returned to the untreated level. Protein kinase C (PKC) inhibitors staurosporine (15 nM) and bisindolylmaleimide I (0.5 microM) also blocked ET effect. After 4 h of cold storage, membrane PKC activity changed little from the prestorage level in the untreated hearts, but was elevated significantly from 52.8 +/- 5.2 pmol/min/mg to 74.7 +/- 8.2 by 20 nM ET (P < 0.05 v untreated). Cytosol PKC did not change during 4 h cold storage with or without ET. Neither end-storage nor end-reperfusion myocardial ATP content was affected by 20 nM ET treatment. In conclusion, ET improves cardiac preservation possibly via bradykinin receptor and PKC without affecting ATP metabolism.

Twenty-four-hour intermittent perfusion storage of the isolated rat heart. II. Perfusion pressure and functional preservation

This study investigated the effect of intermittent perfusion (IP) pressures on functional preservation of the cold-stored isolated rat heart. The heart was flushed with cardioplegic solution #11 with ethylene diamine-tetraacetic acid and 2, 3-butanedione monoxime (CP-11EB), and stored at 0 degree C for 24 hr. During storage, the heart was intermittently perfused for 3 min at 10 and 17 hr of storage with 25 degrees C oxygenated CP-11EB. The IP pressures studied were: 20, 30, 40, 50, 60, 70, 80, and 100 mm Hg. Poststorage recovery of function was assessed with 30 min of working reperfusion. Control function of the unstored heart was: aortic flow (AF), 51.3 +/- 2.2 ml/min; coronary flow (CF), 25.8 +/- 1.2 ml/min; cardiac output (CO), 77.7 +/- 2.3 ml/min; work, 92.0 +/- 4.9 g-m/min; and coronary vascular resistance (CVR), 2.64 +/- .21 mm Hg-min/ml. Functional return in the 30,40,50,60,70, and 80 mm Hg groups was similar. Recovery in a representative group (60 mm Hg) was: AF, 52 +/- 3%; CF, 41 +/- 2%; CO, 48 +/- 3%; work, 42 +/- 3%; and CVR, 225 +/- 10% of the control. The total IP volume in this group was 71.0 +/- 1.7 ml; total lactate dehydrogenase (LDH) release during IP was 8.62 +/- .37 units/g dry; and end-storage tissue lactate was 52.6 +/- 6.4 mumole/g dry. As IP pressure decreased to 20 mm Hg, cardiac functional recovery declined significantly to AF, 35 +/- 6%; CF, 33 +/- 2%; CO, 34 +/- 5%; and work, 27 = 4% of control (P < .05 vs. 60 mm Hg group). The total IP volume decreased to 10.1 +/- .9 ml, tissue lactate content rose to 87.1 +/- 10.9 (P < .05 vs. 60 mm Hg group), but LDH release fell to 5.59 +/- .46 (P < .05 vs. 60 and 100 mm Hg groups). When IP pressure increased to 100 mm Hg, cardiac function was depressed with AF recovered to 25 +/- 3%; CF, 30 +/- 3%; CO, 26 +/- 3%; work, 21 +/- 3%; and CVR, 294 +/- 26% of control (P < .05 vs. 60 mm Hg group). IP volume increased to 100.7 +/- 2.4 ml; total LDH release increased to 19.1 +/- 1.2 (P < .05 vs. 60 mm Hg group), although tissue lactate (58.9 +/- 3.9) was not different from the 60 mm Hg group. End-storage tissue wet/dry weight ratio and myocardial adenosine triphosphate content were not different among the 20, 60, and 100 mm Hg groups. In conclusion, IP has a broad pressure optimum ranging from 30 to 80 mm Hg for 24-hr hypothermic preservation of the rat cardiac explant.

Twenty-four hour intermittent perfusion storage of the isolated rat heart: the effect of perfusion intervals on functional preservation

We investigated the effect of intermittent perfusion intervals on heart preservation. The isolated rat heart was flushed with a cardioplegic solution, CP-11EB, and stored at 0 degrees C for 24 hours. During storage, the heart was perfused periodically at 60 mm Hg for 3 minutes with 25 degrees C oxygenated CP-11EB. The perfusion schedules were as follows: group I, every 4 hours; group II, every 6 hours; group III, every 8 hours; group IV, every 10 hours; group V, 10 and 17 hours of storage; group VI, every 11 hours. Poststorage function was assessed after 30 minutes of working reperfusion. Function of the unstored hearts including aortic flow (51.5 +/- 2.5 ml/min), coronary flow (24.5 +/- 1.3 ml/min), cardiac output (75.6 +/- 3.0 ml/min) and work (85.0 +/- 5.4 g-ml/min) served as controls. Group V hearts were best preserved with aortic flow recovered to 65%; coronary flow 44%; cardiac output 58%; and work 53% of the control. Recovery in group IV was comparable with group V. Groups I, II, III, and VI recovered significantly less than group V. Myocardial adenosine triphosphate content (micromoles per gram dry) in group V was 23.8 +/- 1.7, 20.8 +/- 0.9, 13.5 +/- 2.4, and 15.0 +/- 4.0, at 0, 10, 17, and 24 hours of storage, respectively. Intermittent perfusion at 10 and 17 hours elevated adenosine triphosphate to 99% and 88% of prestorage level. Poststorage reperfusion did not improve improve adenosine triphosphate content (16.2 +/- 2.4) over the end-storage level.(ABSTRACT TRUNCATED AT 250 WORDS)

Enhanced functional preservation of cold-stored rat heart by a nucleoside transport inhibitor

This study investigates the hypothesis that inhibition of nucleoside transport during hypothermic storage elevates tissue adenosine (ADO) content and improves the function of the isolated rat heart. The hearts, flushed with a cardioplegic solution containing varying concentrations (0-100 nM) of a nucleoside transport inhibitor, S-(4-nitrobenzyl)-6-thioinosine (NBTI), were immersion-stored at 0 degrees C for 9 hr. Function was assessed after 30 min of working reperfusion. Function of unstored fresh hearts served as controls and poststorage recovery is reported as percentage of control function. Poststorage heart rate in all groups returned to control level after reperfusion. Recovery of other functional parameters in the no-NBTI group was as follows: aortic flow (AF), 56.2 +/- 4.6%; coronary flow (CF), 53.9 +/- 3.2%; cardiac output (CO), 55.5 +/- 4.0%; systolic pressure, 81.6 +/- 2.5%; work, 47.0 +/- 4.2%; and coronary vascular resistance (CVR), 157.1 +/- 7.8% of control. NBTI improved functional recovery in a dose-dependent fashion; the maximal improvement was seen at a dose of 5 nM, in which the recovery was: AF, 78.1 +/- 3.4%; CF, 73.5 +/- 4.4%; CO, 76.7 +/- 3.6%; work, 70.7 +/- 5.0%; and CVR, 127.5 +/- 4.5% of control (P < 0.05 vs. no-NBTI). The ADO A1-receptor antagonist, 1,3-dipropyl-8-cyclopentylxanthine (0.1 microM) blocked the effects of 5 nM NBTI; the recovery of AF, CF, CO, work, and CVR decreased to 62.8 +/- 8.0%, 58.3 +/- 5.0%, 61.5 +/- 3.9%, 54.4 +/- 4.5%, and 163.8 +/- 12.7% of control, respectively (P < 0.05 vs. 5 nM NBTI). Tissue ADO content in 5 nM NBTI hearts at the end of storage was 0.075 +/- 0.025 mumol/g dry wt, which was significantly elevated from 0.016 +/- 0.004 mumol/g dry wt in no-NBTI hearts. Purine release during initial reperfusion was delayed in 5 nM NBTI hearts, indicating the inhibition of nucleoside transport by NBTI. But NBTI treatment did not improve end-storage or end-reperfusion myocardial ATP. In conclusion, the addition of NBTI to cardioplegic solution enhanced tissue ADO and improved poststorage function of the hypothermically stored rat heart. The effect is ADO A1-receptor mediated without invoking energy conservation.

Deferoxamine given at reperfusion improves function of the cold-stored rat heart

In this study deferoxamine (DF), a strong iron chelator, was administered either before storage or during reperfusion, in an attempt to inhibit the iron-dependent hydroxyl radical production and improve the functional recovery of the cold-stored/reperfused cardiac explant. Excised rat hearts were flushed with Krebs-Henseleit buffer (KHB), arrested with a cardioplegic solution, CP11-EB, with or without DF, and immersion stored in CP11-EB at 0 degree C for 16 hr. To assess function, the stored hearts were reperfused in the working mode with KHB for 30 min. Experimental groups included: (i) DF treatment during prestorage flush [CP11-EB + 0.01 mM (n = 5), 0.05 mM (n = 13), 0.1 mM (n = 5), 0.2 mM (n = 5), or 0.75 mM DF (n = 5)]; (ii) DF treatment during reperfusion [KHB + 0.3 mM (n = 5), 0.6 mM (n = 7), 0.75 mM (n = 11), 1.0 mM (n = 6), 1.5 mM (n = 4), or 2.5 mM DF (n = 7)]; and (iii) untreated group (n = 8) received no DF during flush or reperfusion. Function of unstored hearts (n = 7) including aortic flow (AF, 54.6 +/ 2.6 ml/min); cardiac output (CO, 76.5 +/- 3.3 ml/min), systolic pressure (SP, 135.7 +/- 1 mm Hg), diastolic pressure (DP, 70.7 +/- 3.8 mm Hg), and work (96.7 +/- 6.4 g-meter/min) served as controls. Functional recovery of the untreated group was AF, 59%; CO, 58%; SP, 71%; DP, 73%; work, 41% of control values. DF treatment at any dose during the initial flush did not improve functional recovery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine deaminase inhibitor in cardioplegia enhanced function preservation of the hypothermically stored rat heart

Adenosine (ADO) has been shown to be protective to the ischemic-reperfused myocardium. This study tested the hypothesis that inhibition of myocardial adenosine deaminase during cold storage will elevate tissue ADO content, improve the cardiac function, and preserve ATP. The isolated rat hearts (6-9 hearts/group) were flushed with a cardioplegic solution containing 0-75 microM erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA) and immersion-stored at 0 degree C for 9 hr. Function was assessed after 30 min working reperfusion. Function of the unstored hearts (n = 11, mean +/- SE) including heart rate (293 +/- 13 bpm), aortic flow (AF; 52.5 +/- 1.1 ml/min), coronary flow (CF; 23.5 +/- 1.3 ml/min), cardiac output (CO; 76.0 +/- 2.1 ml/min), systolic pressure (SP; 136 +/- 2 mmHg), diastolic pressure (DP; 63 +/- 1 mm Hg), work (90.5 +/- 3.4 g-m/min), and coronary vascular resistance (CVR; 2.77 +/- 0.14 mmHg-min/ml) served as controls. Heart rate in all stored hearts returned to normal after reperfusion. Recovery of other function in no-EHNA group was: AF, 52 +/- 7; CF, 55 +/- 5; CO, 53 +/- 6; SP, 79 +/- 4; DP, 93 +/- 3; work, 47 +/- 7; and CVR, 171 +/- 15% of control. EHNA improved functional recovery in a dose-dependent fashion. At the optimal concentration of 25 microM, the recovery was: AF, 83 +/- 6; CF, 68 +/- 4; CO, 78 +/- 5; SP, 90 +/- 3; DP, 105 +/- 5; work, 77 +/- 8; and CVR 151 +/- 9% of control. ADO A1 receptor antagonists, 8-phenyltheophylline (1 microM) and 1,3-dipropyl-8-cyclopentylxanthine (0.1 microM) blocked the effects of 25 microM EHNA; the recovery of CO was reduced to 65 +/- 3 and 50 +/- 2% of the control, respectively. Tissue ADO content in 25 microM EHNA hearts at the end of storage was 95 +/- 19 nmol/g dry wt, which was significantly elevated from 15 +/- 3 nmol/g dry wt in no-EHNA hearts. EHNA also caused a 45-fold increase in the release of ADO over no-EHNA group during the first 10 min of reperfusion. But EHNA treatment did not cause any change in either end-storage or end-reperfusion myocardial ATP levels. Thus EHNA in cardioplegic solution inhibited cardiac ADO catabolism during long-term hypothermic storage and improved function preservation partially via an ADO A1 receptor-mediated mechanism without invoking ATP conservation.